This invention refers to apparatus and method for releasably securing a shipping container of standard type (I.S.O. standard) to a loading deck and/or another container within a stack of multiplicity of such containers. More particularly, the invention refers to a new and novel combined horizontal and vertical connector adapted to attachment through openings in corner fittings and/or load decks to cause a container to become interconnected with or coupled to another container or to a loading deck by engagement with the connector.
The prior art equipment for releasably coupling containers to form coherent structures or stacks comprises a variety of distinctly different manually-operated devices each designed for a specific place of use, such as between the deck and the lowermost container, between pairs of adjacent containers, between pairs of stacked containers, or on top of containers. The need to stock a suitable device for use in each of the various positions unduly increases the costs and complexity of the operation.
U.S. Pat. No. 3,691,595 summarizes the state of the art and provides a partial solution to the above described problem of stocking a large inventory of different devices by providing a vertical connector having a twist-lock for penetration into the elongate orifice of a corner fitting, the twist-lock automatically activated by the vertical compression caused by the weight of a gravitating container to release a force for rotation of the twist-lock towards a locking position. A special tool is needed to prepare the vertical connector prior to each use and for the manual release of the activated twist-lock during disassembly of the stacked containers.
While substantially eliminating some of the drawbacks of the prior art, U.S. Pat. No. 3,691,595 does not eliminate the need for a separate coupling device for horizontal coupling. Also, because the device includes active elements which require the use of a manually-operated special tool for unlocking, many of the problems associated with the uncoupling of vertical connectors located at interior positions in a stacked block of containers remain unsolved, inasmuch as stevedores must still climb up and down the container stack in order to release each locking mechanism prior to vertical separation of the containers.
Thus, the need still exists for a simple, rugged device, preferably without active elements subject to failure, which does not require a special tool or human interaction for unlocking, and which is simultaneously capable of releasably coupling containers horizontally as well as vertically.